差示扫描量热仪测定比热容方法的改进

对用常规热流型DSC仪测量物质比热容时的两个误差来源,即实际的升温速率偏离了程序设定的升温速率以及试样铝盘与参比铝盘两者质量的差异造成的影响进行数学分析,导出了计算比热容的改正方程.此方程的第一项HFT为实验热流值与实际升温速率的比值,第二项为测试过程中由于样品盘与参比盘的质量不同所引起的修正项，从而提高了测量结果的精确度.用此方法测量水、苯甲酸和氯化钾的比热容均得到较好的结果.

Modification of DSC Method for Measuring Specific Heat Capacity

Specific heat capacity(c_p) is a fundamental thermodynamic property.Its traditional measurement method by DSC requires three scans: a baseline scan,a scan using a sapphire standard,and the sample scan.The paper modifies the traditional DSC measurement method to eliminate two sources of error.Namely they are inequality of the weight of the two empty aluminum pans for sample and reference and the departure of actual heating rate to that of programmed heating rate.A modified formula considering these two effects is given.The first term HFT is the ratio of heat flow to actual heating rate;while the second term is a correlation factor that caused by the weight difference of sample and reference aluminum pan.The modified method offers a significant advance in the ease and reliability of measuring c_p for the testing material of water,benzoic acid and potassium chloride.